| Title: |
Distinct transient structural rearrangement of ionized water revealed by XFEL X-ray pump X-ray probe experiment |
| Authors: |
Stransky, M.; Lane, T.; Gorel, A.; Boutet, S.; Schlichting, I.; Mancuso, A.; Jurek, Z.; Ziaja, B. |
| Source: |
arXiv |
| Publication Year: |
2024 |
| Collection: |
Max Planck Society: MPG.PuRe |
| Description: |
Using X-ray free electron laser (XFEL) radiation to conduct an X-ray pump X-ray probe experiment, we studied strongly ionized water as part of our ongoing work on radiation damage. After irradiance with a pump pulse with a nominal fluence of ~5×105 J/cm2, we observed for pump-probe delays of 75 fs and longer an unexpected structural rearrangement, exhibiting a characteristic length scale of ~9 Å. Simulations suggest that the experiment probes a superposition of ionized water in two distinct regimes. In the first, fluences expected at the X-ray focus create nearly completely ionized water, which as a result becomes effectively transparent to the probe. In the second regime, out of focus pump radiation produces O1+ and O2+ ions, which rearrange due to Coulombic repulsion over 10s of fs. Importantly, structural changes in the low fluence regime have implications for the design of two-pulse X-ray experiments that aim to study unperturbed liquid samples. Our simulations account for two key observations in the experimental data: the decrease in ambient water signal and an increase in low-angle X-ray scattering. They cannot, however, account for the experimentally observed 9 Å feature. A satisfactory account of this feature presents a new challenge for theory. |
| Document Type: |
article in journal/newspaper |
| File Description: |
application/pdf |
| Language: |
English |
| Availability: |
https://hdl.handle.net/21.11116/0000-000E-7455-0; https://hdl.handle.net/21.11116/0000-000E-7457-E |
| Rights: |
info:eu-repo/semantics/openAccess |
| Accession Number: |
edsbas.293E857F |
| Database: |
BASE |